Patent GB-201943-A (GB)
Title: Improvements in photographic shutters
IPC: G03B9/22
Filed: 1923-08-07
Abstract: 201,943. Klein, R. Aug. 4, 1922, [Convention date]. Shutters with pivoting blades.- The shutter blades are mounted in one casing A, Figs. 1 and 2, and can be operated directly, as by a projection 22, for focussing or for a time exposure, and another casing B which is connected by a tubular connection 48 with the casing A contains mechanism for operating the blades for time, bulb or instantaneous exposures by means extending through the connection 48. In the casing A the blades 1, Fig. 5, are mounted in the space between a cover plate 10, Figs. 5 and 13, which is fixed to the annular portion 2 of the lens tube 12 by screws 11, and a bearing plate 5 which is clamped on to the same portion 2 by bolts 3, Figs. 5 and 14. The blades are slotted at the outer ends to engage and pivot on the bolts 3, and are engaged by bolts 8 extending from an operating ring 7 mounted to turn on flanges 5<a> of the bearing plate 5. The operating ring 7 has a projection 20, Fig. 6, extending through the annular portion 2 and is operated by the slot 24 of a spring controlled lever 22 pivoted on the portion 2 which can be operated by hand to open the blades. A cover plate 27, Fig. 2, has a slot 29 through which the end of the lever 22 projects. A cover plate 10<a> having a lens flange 13 is secured over the shutter blades and carries an iris diaphragm which is set by a rotating ring 15 having a graduated plate 18 moving over a pointer 19 on the shutter casing. The connecting tube 48, Fig. 4, is screwed on to the casing B and to the cover plate 27 and a connecting rod 51 through the tube 48 abuts against the lever 22 and is pivoted at 52 to the exposure lever 44 in the casing B. The operating mechanism in the casing B, Figs. 17 and 18, consists of a spring-controlled actuating lever 38, pivoted at 39, a spring-controlled two-armed master member 34, 35 pivoted at 33, which is moved by the actuating lever 38 and itself operates the spring controlled shutter operating member 44 pivoted at 45, and a detent member 54 pivoted at 55 on the casing, and carrying a latch 58 pivoted to it at 59. The latch is acted on by a spring round the pivot 55. The movement of the detent 54 is controlled for bulb, time and instantaneous exposures by a pin 69 on the detent and the cam surface 85, Fig. 20, of a setting plate 79, having a setting mark 81, Fig. 1, which is set to the scale on a stationary cover 31 mounted bv lugs 83 on the casing. On actuating the lever 38 when the shutter is set for time exposures, (1) the turned end 42, Fig. 17, on the actuating lever 38 raises and passes over, the arm 34 of the master member and causes the end of the arm 35 to ride over and spring behind a wedge flange 47 of the operating member 44, Fig. 18, (2) a projection 64 on another arm of the lever 38 rides over the projection 65 of the detent 54 and engages between it and a projection 70 of the latch 58 the lever 38 being thereby prevented from fully returning to normal position; and (3) the end 62 of an arm 56 on the detent 54 engages behind a projection 63 on the arm 35 so as to hold the member 44 in the position in which the blades of the shutter are open. On re-actuating the lever 38 the projection 64 acts on the projection 70 and swings the latch 58 and with it the detent 54, releasing the projection 63 and arm 35 and so permitting the members 35 and 44 to complete their movements to normal position. When set for bulb exposures the movement of the pin 69 and detent 54 is controlled so that on actuating the lever 38 the end 62 of the arm 56 engages the arm 35 of the master lever to hold the shut:er open as before. The projection 64 is, however, not engaged behind the projection 65 but engages under the projection 70 and when released rocks the detent 54 and disengages the end 62 from the projection 63, the arm 35 and operating member 44 thereupon completing their movement. For instantaneous exposures the detent 54 and the latch are inoperative, and after the end 42 of the release lever passes over the arm 34, the parts return freely to starting position. For controlling the exposure an arm 72 on a wheel 71 coupled with retarding mechanism can be moved to engage the pin 52 on the operating member 44, and oscillates with it after engagement and to an extent controlled by the setting of the pin 74 by another cam 86 on the setting disc 79. The return movement of the arm 72 is effected by the spring 73 acting on the pin 74. The retarding mechanism includes an anchor 77 and escapement wheel.